Why coffee isn’t working for you anymore, and what you can do about it

By Jonathan Ford Hughes
Published October 26, 2021

Key Takeaways

In doctors’ lounges across the country, cups of coffee are about as ubiquitous as white coats. However, like many other drugs, caffeine has adverse effects, and caffeine users often experience the dreaded “coffee crash.” And yet, coffee remains a mainstay in American medicine.

And it isn’t just American doctors who run on caffeine. A 2015 BMJ study examined the coffee-consumption habits of 766 Swiss medical doctors of various specialties. Among them, 84% purchased coffee on the job, totaling nearly 71,000 cups of coffee in a single year. Of note: This does not include coffee that the physicians may have already guzzled at home, or on their way to work. Researchers determined that orthopedic surgeons drank the most coffee at work, and anesthesiologists drank the least.

Is this problematic? While coffee has documented health benefits, including a recent review that highlighted its effects on depression, most regular coffee-drinkers are familiar with the precipitous energy crash that follows the initial caffeine buzz. Let’s be clear: We’re not telling you to give up your cup of joe. We’re suggesting that maybe there’s a better way for doctors to reap its energetic and health benefits. Here’s the why and how behind the energy roller-coaster that is coffee, and how you can avoid it.

A hyper-focused beginning

Starbucks connoisseurs are likely familiar with its marketing slogan: “That first sip feeling.” There’s a biochemical explanation behind it. 

It starts with adenosine, a central nervous system (CNS) neuromodulator with specific receptors in the CNS. Under caffeine-free circumstances, adenosine follows a natural ebb and flow, binding to receptors as our day winds down, making us feel drowsy and dilating blood vessels, likely to promote oxygen flow while we sleep.

Coffee alters this natural cycle, and it’s a one-two punch. The caffeine that comes along for the ride is an adenosine-receptor antagonist. It binds to adenosine receptors, preventing adenosine from making us feel drowsy. 

The energetic kick is a secondary effect. With the adenosine receptors occupied by molecules of sweet, sweet caffeine, the pituitary gland tells the adrenals to add a little adrenalin to the mix. Now, not only are you feeling less tired, but you’re buzzing with the fight-or-flight energy of adrenalin. A few sips later and you’re ready to solve the next great medical mystery.

A precipitous crash

Then, your energy plummets. You sneak to the on-call room for a nap … or reach for another cup of coffee. Why?

A 2021 StatPearls update offers some insights. Regular caffeine users appear to have more adenosine receptors in their CNS, making them more sensitive to the drowsiness-inducing effects of adenosine. In other words, after the bodies of coffee-connoisseurs metabolize the caffeine from their morning flagons of java, adenosine has more opportunities to do its thing. 

This differs from drugs such as cocaine or amphetamines in one key way: While cocaine and caffeine are both dopaminergic, in the former, the dopaminergic activity takes place in the nucleus accumbens, and in the latter, it occurs in the prefrontal cortex. The nucleus accumbens is where the brain sorts out motivation and action, and it has an essential role in behaviors related to feeding, sex, reward-seeking, stress, and drug self-administration. On the other hand, the prefrontal cortex is the hub of cognitive control. Dopamine there influences attention, impulse inhibition, cognitive flexibility, and prospective memory. According to StatPearls, the dopamine boost here has a reinforcing property–in this case sending us back for more coffee!

In other words, we may have a coffee-crash because the habitual coffee drinkers among us have more adenosine receptors–and that crash is part of a dopaminergic, negative feedback loop that keeps us reaching for another cup, and another, and another …

This is where we start to teeter into the realm of caffeine addiction, a DSM-recognized disorder. You can read more about that, and how it may affect physicians, here.

There’s got to be a better way.

What you can do about it 

Why are you drinking so much coffee in the first place? Sleep deprivation may have something to do with it. And unfortunately, coffee may be exacerbating your sleep woes. Have you heard of the coffee cycle? It’s not the rapid-brew setting on your coffee maker, but a common cycle of feeling tired, drinking excess caffeine, and then messing up your sleep pattern as a result. Rinse and repeat.

We know, for example, that consuming caffeine less than 6 hours prior to bedtime can disturb sleep significantly, compared with placebo. We also know that caffeine can disrupt sleep cycles, shifting rapid-eye movement earlier in the night, and pushing deeper sleep stages to the end of the night, which is a problem during a shortened sleep period. Taking all of that into consideration, it would seem that: a) prioritizing sleep (tips on that here) and b) ending caffeine intake earlier in the day, are sound tactics.

The final proven tactic is to limit intake. Caffeine has a long half-life–about 5 hours–so downing your typical gallon of coffee before the aforementioned 6-hour window closes will do you little good. You’ll still be metabolizing that caffeine while you sleep, and messing up your sleep cycle in the process. Research indicates you should stick to fewer than 400 mg daily. For context, the average 8 oz cup of coffee has about 95 mg of caffeine. At this threshold, there’s no association with adverse effects on bone health, behavior, cancer risk, male fertility, or cardiovascular health. For pregnant or nursing women, research suggests keeping it to fewer than 200 mg daily.

Should you quit coffee? We’ll leave that up to you. You would be missing out on the documented health benefits, such as enhanced cognitive performance, fat metabolism, and decreased risk of Parkinson and Alzheimer disease, among others. One thing is certain: If you decide to quit, don’t do it cold turkey. Withdrawal symptoms include fatigue, headache, and mood changes. You can expect symptoms to start cropping up the morning after you quit, with the peak occurring between 20-51 hours later. Try cutting back slowly instead of quitting all at once.

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